Inactivated influenza virus vaccine for nasal or oral application

ABSTRACT

The invention relates to nasal or oral administration of a compound containing inactivated influenza virus antigen and aluminum as adjuvant for the prophylaxis of influenza virus infections. Said vaccine is especially suitable for inducing a mucosal IgA immune response and systemic IgG immune response.

This application is a continuation of U.S. Ser. No. 10/639,449 filedAug. 13, 2003 now U.S. Pat. No. 6,861,244, which is a continuation ofU.S. Ser. No. 09/913,400 filed Dec. 5, 2001, now U.S. Pat. No.6,635,246, which is 371 of PCT/AT00/00023 filed Feb. 1, 2000, both ofwhich are hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to a vaccine composition containing at least oneinactivated influenza virus antigen and aluminum as an adjuvant fornasal or oral application for the prophylaxis of influenza virusinfections.

BACKGROUND OF THE INVENTION

Influenza virus infections represent an ever greater health risk,especially in the elderly and in persons with chronic diseases, becausethe infection in these groups often leads to higher mortality rates.Since the introduction in the 1940s of an inactivated influenza vaccinecontaining inactivated virus material from infected incubated eggs, therisk and course of the infection as well as the mortality rates inelderly persons have dropped.

To date, inactivated influenza virus vaccines from eggs are licensed forparenteral administration to people, and induce anti-HA-IgG antibodiesin the serum. The cross-protection against heterologous influenzaviruses, however, can be traced primarily to the cross-reactivity of IgAantibodies in a natural infection. (Liew et al., 1984, Eur. J. Immunol.14:350–356). Therefore, with the development of new immunization methodsagainst influenza virus infections, an attempt is being made tostimulate the production of the mucosal IgA immune response.

To this end, a series of developments for intranasal or oraladministration of influenza virus vaccines has been developed. Thus, forexample, the administration of an inactivated virus vaccine (Waldman etal., 1968, Nature 218:594–595), an inactivated vaccine combined withcarboxyvinyl polymer (Oka et al., 1990, Vaccine 8:573–576), or withpertussis toxin B oligomer (Oka et al., 1994, Vaccine 12:1255–1258), asplit virus vaccine with cholera toxin, E. coli heat-labile enterotoxinor liposomes (Tamura et al., 1992, J. Immunol. 149:981–988, Komasse etal., 1998, Vaccine 16:248–254, de Haan, 1995, Vaccine 13:155–162), anemulsion inactivated vaccine (Avtushenko et al., 1996, J. Biotechnol.44:21–28), or a cold adapted live attenuated influenza virus vaccine(Belshe et al., 1998, N. Engl. J. Med. 338:1405–1412) produces not onlythe induction of HAl-IgG antibodies in the serum, but also the secretionof IgA antibodies of the mucosal membrane as well.

Inactivated viruses as orally or nasally applied vaccines must, however,be given in high concentrations in order to bring about a significantincrease of antibodies. The administration of inactivated influenzavirus or antigen in convenient commercial doses, free of side effects,with nasal or oral administration, does not produce a satisfactoryimmune response without the use of an adjuvant. (Chen et al., 1989,Current Topics in Microbiology and Immunology 146:101–106, Couch et al.,1997, J. Infect. Dis. 176:38–44). Thus, for example, for the optimuminduction of the immune response with oral administration of anemulsion-inactivated vaccine, an antigen content between 66 μgantigen/dose and 384 μg antigen/dose is required (Avtushenko et al.,1996, J. Biotechnol. 44:21–28). Thus, this dose lies far above that ofan inactivated vaccine for parenteral administration, which is atapproximately 15 μg antigen/dose.

Although cholera toxin, E. coli heat-labile toxin and pertussis toxinhave an effective adjuvant effect in oral or nasal administration ofinfluenza antigen, they are not used for human application because ofthe toxic side effects. The only adjuvant approved to date forapplication to humans is aluminum.

A cold-adapted, live attenuated influenza virus vaccine to be found inclinical studies for nasal administration is based on virus antigensfrom which reassortants must be produced annually by means of geneticmethods, in which the genes for the hemagglutinin and neuramidaseantigens of the corresponding influenza A or B strain are transferred toan attenuated, cold-adapted master virus strain. This method is verytime consuming and labor intensive. In addition, there is the dangerthat through reversion the attenuated virus back mutates into a virulentvirus and thus can trigger viremia. When immunization is carried outwith living viruses there is also a further spread in the body of theimmunized individual. When cold-adapted viruses are used, there is alsothe constant necessity of storing the virus vaccine below the freezingpoint, as close to −20° C. as possible, which then requires the absolutemaintenance of a chain of refrigeration to ensure sufficient storagelife of the vaccine.

Eggs are used for the production of the virus reassortants and thepropagation of the vaccine viruses, which entails the risk that anycontaminating infectious agents that may be present may be transferredinto the eggs. The purification of live viruses is also not withoutproblems because they represent infectious material and thus a higherstandard of security must be maintained.

The problem of the present invention is, therefore, to make available aninfluenza virus vaccine composition that does not have the disadvantagesdescribed above, and that effectively induces the IgA and IgG immuneresponse in mammals.

BRIEF SUMMARY OF THE INVENTION

The problem is solved according to the invention by the use of a vaccinecomposition containing at least one inactivated influenza virus orinfluenza virus antigen and aluminum as an adjuvant for nasal or oraladministration. The composition described is suitable in particular as avaccine for the prophylaxis of influenza virus infections.

In the context of the present invention, it was shown that aninactivated influenza virus vaccine containing aluminum as adjuvant fornasal or oral administration triggers an effective IgG as well as IgAimmune response in mammals. This was especially surprising because withthe approaches to date towards the development of affective influenzavirus vaccines it was found that the adjuvant effect of aluminum inelevating the immunogenicity of the antigen is very slight, even in avaccine for parenteral administration (Davenport et al., 1968, J.Immunol. 100:1139–1140).

Furthernore, it was found that with the nasal or oral application of thevaccine composition according to the invention a considerably higher IgGand IgA titer as well as a higher HAl titer is achieved in mammals thanwith the vaccine formulations known to date that contain either onlyinactivated influenza viruses, inactivated viruses with cholera toxin,or live viruses (Table 1).

Therefore, the application according to the invention is suitable inparticular for the induction of a protective mucosal IgA and a systemicIgG immune response.

Since aluminum is the only adjuvant approved for application in humans,the application, according to the invention, of the vaccine combinationof inactivated influenza virus and aluminum has the great advantage thatit can be administered directly to humans without any problem. Thespecial advantage of the use according to the invention, therefore,aside from the elevated immunoreactivity of the vaccine composition fornasal or oral administration is that through use of an adjuvant that hasbeen tested over a number of years and whose application to humans isapproved, the vaccine is completely free of side effects.

DETAILED DESCRIPTION

For use according to the invention, the composition can contain aluminumpreferably in the form of aluminum hydroxide (Al(OH)₃) or aluminumphosphate (AlPO₄). In this case, the concentration of the aluminum ispreferably in a final concentration of 0.05% to 0.5%.

The influenza virus antigen quantity in the vaccine in this case is thecustomary antigen quantity for a vaccine dose. Preferably, the antigenquantity that is contained in a vaccine dose is between 1.5 μgantigen/dose to 50 μg antigen/dose in humans.

The influenza virus antigen can be produced from infected eggs viaconventional methods, and purified.

Preferably, however, the virus antigen is obtained from an infected cellculture, such as described, for example, in WO 96/15231. Particularlypreferred for the use according to the invention to produce an influenzavirus vaccine is an influenza virus antigen that is obtained from a VEROcell culture infected with influenza virus that is cultured in a serumand protein-free medium. The virus antigen obtained from the infectedcell culture is first inactivated with formalin and can then be obtainedas a purified, concentrated virus antigen preparation by means ofcontinuous density gradient centrifugation, DNAse treatment,diafiltration, and sterile filtration. This concentrated preparation canthen be used together with aluminum as an adjuvant for the use accordingto the invention to produce a vaccine for nasal or oral administration.

A special advantage in the production of the vaccine is that the virusmaterial is inactivated before purification, and so in comparison to thepurification of attenuated live viruses, a considerably higher degree ofpurity of the antigen preparation is achieved.

A particular advantage in the use of influenza virus antigens obtainedfrom a serum and protein-free cell culture infected with influenza virusis the absence of egg-specific proteins that could trigger an allergicreaction against these proteins. Therefore, the use according to theinvention is especially suitable for the prophylaxis of influenza virusinfections, particularly in populations that constitute higher-riskgroups, such as asthmatics, those with allergies, and also people withsuppressed immune systems and the elderly.

The Vaccine can be Applied in Different Ways

According to one embodiment of the invention, the intranasaladministration is via the mucosal route. The intranasal administrationof the vaccine composition can be formulated, for example, in liquidform as nose drops, spray, or suitable for inhalation, as powder, ascream, or as emulsion.

The composition can contain a variety of additives, such as stabilizers,buffers, or preservatives.

For simple application, the vaccine composition is preferably suppliedin a container appropriate for distribution of the antigen in the formof nose drops or an aerosol.

According to another embodiment of the invention, the administration isoral and the vaccine may be presented, for example, in the form of atablet or encased in a gelatin capsule or a microcapsule, whichsimplifies oral application. The production of these forms ofadministration is within the general knowledge of a technical expert.

The invention will be explained in more detail on the basis of thefollowing examples, whereby it is not limited to the examples.

EXAMPLES Example 1

Production of an Influenza Virus Vaccine Preparation

Influenza virus was obtained from a protein-free VERO cell cultureinfected with influenza A or B virus strain, according to WO 96/15231 oraccording to conventional methods from allantoic fluid from infected,incubated chicken eggs.

For the production of an inactivated influenza virus preparation fromcell culture, the supernatant of an infected VERO cell culture to whichformalin (final concentration 0.025%) was added, and the viruses wereinactivated at 32° C. for 24 h. This material was purified by zonalcentrifugation in a continuous 0–50% sucrose gradient, DNAse treatment,diafiltration, and sterile filtration. The purified material was storedat −70° C. The final product was tested for residual contamination andthe following criteria were established per dose:

Hemagglutinin content: ≧15 μg HA per strain Protein content: ≦250 μgSucrose content: ≦200 mg Formalin content: ≦5 μg Benzonase content: ≦5ng Residual DNA (VERO): ≦100 pg Endotoxin content: ≦100 EU Pyrogen: free

Example 2

Intranasal Immunization of Mice with Different Influenza VirusPreparations

The antigen preparations from Example 1 were diluted in PBS to an HAantigen content of 15 μg/mL and optionally Al(OH)₃ added to a finalconcentration of 0.2%, or cholera toxin. For the production of apreparation for intranasal immunization of mice, the solution wasdiluted to the appropriate quantity of antigen with PBS, optionallycontaining Al(OH)₃ or cholera toxin.

Four Balb/c mice each received intranasal immunization with differentinfluenza virus preparations, and in each case, 50 μL of a solutioncontaining influenza virus antigen and optionally an adjuvant wereadministered drop-wise into the nostrils of the mice. The firstimmunization was given on Day 0, the second on Day 7, and the third onDay 14. On the 28th day the IgG, IgA, and HAl titers in serum, saliva,and pulmonary lavage were determined.

Table 1 shows the plan of the intranasal immunization of the individualmice groups with different influenza virus preparations.

TABLE 1 Vaccination plan for the intranasal immunization of mice GroupBalb/c mice Antigen Dose Route 1. Group Inactivated whole 1 μg HA 50μl/i.n. viruses from VERO cells 2. Group Inactivated whole 1 μg HA 50μl/i.n. viruses from infected eggs 3. Group Live viruses from 5 × 10⁶EID₅₀ 50 μl/i.n. VERO cells 4. Group Live viruses from 5 × 10⁶ EID₅₀ 50μl/i.n. infected eggs 5. Group VERO mock 5% of 1 μg 50 μl/i.n.preparation 6. Group Egg mock 5% of 1 μg 50 μl/i.n. preparation

Example 3

Determination of the IgA Titer in the Saliva, Pulmonary Lysate, andSerum, as Well as of the IgG Titer and HAl Titer in the Serum

On Day 28 after immunization, saliva, pulmonary, and serum specimenswere taken from the animals, and the antibody titer in the individualspecimens was determined.

Saliva specimens were collected by injection of 0.5 mL PBS into the oralcavity of the mouse, and the presence of IgA antibodies was tested.

To produce pulmonary lysate specimens, the mice were killed, the thoraxopened, and the lungs removed and washed with PBS. Subsequently, thelungs were ground and the homogenate centrifuged in order to remove celltissue. The supernatant was collected and stored at −20° C. untiltesting for IgA antibodies.

The IgG and IgA antibody titer was determined with a commercialinfluenza virus Type A and B ELISA test (Genzyme Virotech). After a 2 hincubation at 37° C., the specific IgG and IgA antibodies were detectedwith conjugated goat anti-mouse IgG or IgA (Pharmigen) and chromogenicsubstrate containing H₂O₂ and o-phenyldiamine.

To determine the HAl titer, blood was taken from the mice, and the serumobtained was tested in the influenza A or B hemagglutination test (HAltiter) according to the method of Palmer et al. (1975, Advancedlaboratory technicals [sic; techniques] for immunological diagnostic,U.S. Dept. Health. Ed. Welfare. P.H.S. Atlanta, Immunology Ser. No. 6,Procedural guide, part 2, hemagglutination inhibition test, pp. 25–62).

Table 2 shows a summary of the determination of the IgA antibody titerin the saliva, pulmonary lysate, and serum, and the IgG antibody titeras well as HAl titer in the serum. The data clearly indicate thatneither the IgA nor the IgG immune response is stimulated by aninactivated whole virus vaccine without adjuvant. On the other hand, ifthe immunization is done with live virus or inactivated whole virus towhich cholera toxin has been added, an increase of the IgA, IgG, and HAltiters takes place in the mice, just as after immunization withinactivated whole virus to which aluminum has been added, whereby withthe latter vaccine, the IgG immune response in the serum was actuallythe highest of all preparations tested. Likewise, the highest HAl titerwas measured for the inactivated vaccine with aluminum.

The results show that the intranasal immunization with inactivatedinfluenza virus vaccine to which aluminum has been added induces aslightly increased IgA immune reaction in comparison to the knowninfluenza virus vaccine preparations, and a considerably higher IgGimmune response in mammals, without having the disadvantages of a livevirus vaccine or a vaccine to which an adjuvant has been added that hasnot been approved for application to humans, such as cholera toxin.

Example 4

Storage Stability of the Vaccine Composition at Different Temperatures

For stability investigations, the monovalent bulks (MB) of the influenzavirus vaccination strains Johannesburg 82, Nanchang and B/Harbin werestored for 12 months at +4° C., −20 C, and −80° C. After 6 and 12months, the specific hemagglutination test (HA) content of the MBsJohannesburg 82 (MB/J/0197), Nanchang (MB/N/0197), and B/Harbin(MB/H/0397) without Pluronic, as well as Johannesburg 82 (MB/J/0297P),Nanchang (MB/N/0297P), and B/Harbin (MB/H/0497P) with Pluronic wasdetermined by means of a SRD (single radial immunodiffusion) assayaccording to Wood et al., 1977, J. Biol. Standard 5:237–247, and thedeviation from the initial value was calculated in percent.

The trivalent bulks (TVB) 410197 (without Pluronic) and 4102997P (withPluronic) were also stored for 12 months at +4° C., and then tested inthe SRD assay. Furthermore, the reserve samples of these MBs and TVBsthat had been stored at room temperature for sterility testing wereanalyzed in the SRD assay after 12 months.

The results of the MBs are given in Table 3, and the results of the TVBsin Table 4:

The storage of the MBs at +4° C. and −80° C. for 1 year show practicallyno reduction of the specific HA content compared with the initial valuein the case of Johannesburg 82 and Nanchang. The B/Harbin preparationsappear to be less stable; they drop by about 25% (without Pluronic) andabout 40% (with Pluronic). Storage at −20° C. appears to have asignificant influence on the stability; for Johannesburg 82, the valuesdrop by 27% (without Pluronic) or 11% (with Pluronic), for Nanchang by9% (without Pluronic) or 19% (with Pluronic), and for B/Harbin by 34%(without Pluronic) or 47% (with Pluronic). The results of storage atroom temperature indicate an astounding stability of the preparation.For Johannesburg 82, approximately 80% of the original HA content canstill be detected, for Nanchang ca. 65%, and for B/Harbin about 45%.Storage of the TVBs at +4° C. for 1 year again shows no significantdifference in the HA content. The stability of the TVBs at roomtemperature for 1 year differs in the 3 strains: for Johannesburg 82there is no significant difference in the HA content, for Nanchang aslight reduction (about 10%), and for B/Harbin a drop of approximatelyone third.

Overall, the preparations are very stable, even with storage at roomtemperature, and there is no significant difference between thepreparations with and without Pluronic.

This application claims priority to A194/99 filed Feb. 11, 1999, theentirety of which is hereby incorporated by reference.

TABLE 2 Intranasal immunization of mice with different influenzapreparations, and determination of the IgA titer in the saliva,pulmonary lysate, and serum and the IgG titer as well as HAI titer inthe serum Titer IgA IgG HAI Immunogen Strain Adjuvant Saliva Pulmonarylysate Serum Serum Johann 82 Nanchang B/Harbin Vero Vaccine J, N, H FluA Flu B Flu A Flu B Flu A Flu B Flu A Flu B A/H1N1 A/H3N2 B(inactivated) — <10 <10 <10 <10 <10 <10 800 100 80 80 20 Al(OH)₃ 40 10320 40 160 <10 102.400 3.200 1.280 640 160 CTB 20 10 n.b. n.b. 80 <1051.200 12.800 640 640 160 Egg vaccine J, N, H — 10 10 10 <10 <10 <101,600 100 160 160 40 (inactivated Al(OH)₃ 40 20 320 40 160 10 51.2006.400 640 320 160 Live virus, N — 20 <10 n.b. n.b. 160 <10 51.200 <10 80640 <10 Vero Live virus, N — 40 <10 n.b. n.b. 160 <10 51.200 <10 80 32020 egg Vero Mock — <10 <10 <10 <10 <10 <10 <10 <10 80 160 20 — Al(OH)₃<10 <10 n.b. n.b. <10 <10 <10 <10 80 160 <10 CTB <10 <10 n.b. n.b. <10<10 <10 <10 80 160 <10 Egg Mock — — <10 <10 <10 <10 <10 <10 <10 <10 80160 20 — Al(OH)₃ <10 <10 <10 <10 <10 <10 <10 <10 80 160 20 J:Johannesburg 82 (A/H1N1), N: Nanchang (A/H3N2), H: B/Harbin, n.b. = notdetermined

TABLE 3 Storage stability of the MBs of influenza vaccine for the season1997/98 I Lot Storage 0 Months 6 Months 12 Months Johannesburg MB/J0197+4° C. 184 μg 204 μg [111%] 189 μg [103%] 82 −20° C. 182 μg [99%] 134 μg[73%] −80° C. 210 μg [114%] 187 μg [102%] RT — 152 μg [83%] MB/J/0297P+4° C. 198 μg 230 μg [116%] 207 μg [105%] −20° C. 202 μg [102%] 177 μg[89%] −80° C. 226 μg [114%] 212 μg [107%] RT — 161 μg [81%] NanchangMB/N0197 +4° C. 126 μg 130 μg [103%] 131 μg [104%] −20° C. 124 μg [98%]115 μg [91%] −80° C. 143 μg [114%] 132 μg [105%] RT — 83 μg [66%]MB/N/0297P +4° C. 140 μg 128 μg [91%] 134 μg [96%] −20° C. 139 μg [99%]113 μg [81%] −80° C. 143 μg [102%] 150 μg [107%] RT — 90 μg [64%]B/Hardin MB/H/0397 +4° C. 116 μg 89 μg [77%] 83 μg [72%] −20° C. 101 μg[87%] 76 μg [66%] −80° C. 97 μg [84%] 88 μg [76%] RT 324 μg — 148 μg[46%] MB/H/04/97P +4° C. 146 μg 95 μg [65%] 87 μg [60%] −20° C. 108 μg[74%] 77 μg [53%] −80° C. 105 μg [72%] 89 μg [61%] RT 374 μg — 159 μg[43%] RT: Room temperature P: with Pluronic Data on the specifichemagglutination (HA) content given per mL and in brackets, data on theHA content compared to the initial value given in percent

TABLE 4 Storage stability of the influenza vaccine for the season1997/98 II Storage of the TVBs (trivalent bulk) at +4° C. and at roomtemperature Storage 12 months Strain Lot Pluronic 0 Months +4° C. Roomtemperature Johannesburg 82 410198 − 16.8 μg 17.5 μg [104%] 15.8 μg[94%] Nanchang 410198 − 15.9 μg 16.3 μg [103%] 14.1 μg [89%] B/Harbin410198 − 16.3 μg 14.1 μg [87%] 10.6 μg [65%] Johannesburg 82 410298P +16.9 μg 17.4 μg [103%] 17.3 μg [102%] Nanchang 410298P + 15.4 μg 13.9 μg[90%] 13.9 μg [90%] B/Harbin 410298P + 14.5 μg 14.1 μg [97%] 9.7 μg[67%] Data on the specific hemagglutination (HA) content per dose (=0.5mL), and in brackets data on the change of the HA content compared tothe initial value given in percent

1. A method of enhancing IgA and IgG immune response in a mammal againstinfluenza, wherein the method comprises orally administering to themammal a storage-stable vaccine comprising inactivated influenza virusantigen and an aluminum salt and is free of media proteins, wherein theantigen is treated by one or more steps selected from the groupconsisting of centrifugation, DNAse treatment, diafiltration and sterilefiltration.
 2. The method according to claim 1, wherein systemic levelsof IgG are elevated.
 3. The method according to claim 1, wherein mucosallevels of IgA are elevated.
 4. The method according to claim 1, whereinaluminum salt is aluminum hydroxide or aluminum phosphate.
 5. The methodaccording to claim 1, wherein the antigen is present at 1.5 μg to 50 μgper vaccine dose.
 6. The method according to claim 1, wherein thealuminum salt is present in a concentration of 0.05% to 0.5%.
 7. Themethod according to claim 1, wherein the antigen is present at 1.5 μg to50 μg per vaccine dose and the aluminum salt is present in aconcentration of 0.05% to 0.5%.
 8. The method according to claim 1,wherein the mammal is a human.
 9. A method of enhancing IgA and IgGimmune response in a mammal against influenza, wherein the methodcomprises nasally administering to the mammal a storage stable vaccinecomprising inactivated influenza virus antigen and an aluminum salt andis free of media proteins, wherein the antigen is treated by one or moresteps selected from the group consisting of centrifugation, DNAsetreatment, diafiltration and sterile filtration.
 10. The methodaccording to claim 9, wherein systemic levels of IgG are elevated. 11.The method according to claim 9, wherein mucosal levels of IgA areelevated.
 12. The method according to claim 9, wherein aluminum salt isaluminum hydroxide or aluminum phosphate.
 13. The method according toclaim 9, wherein the antigen is present at 1.5 μg to 50 μg per vaccinedose.
 14. The method according to claim 9, wherein the aluminum salt ispresent in a concentration of 0.05% to 0.5%.
 15. The method according toclaim 9, wherein the antigen is present at 1.5 μg to 50 μg per vaccinedose and the aluminum salt is present in a concentration of 0.05% to0.5%.
 16. The method according to claim 9, wherein the mammal is ahuman.